With the proliferation of electronic typewriters, the typewriter has become a computer controlled printer with a keyboard input device. As long as the operations of the printer are capable of being broken down into the discrete operational steps of the printer, such as escapement, paper feed, tabulation, printing and carrier return, the computer may control the printer operation in ways that are very beneficial to the operator in that the operator is relieved of the need to memorize information or requirements for producing documents and correspondence that are not only correct but pleasing in appearance.
For example, envelopes have a predesignated position for each of the return address, addressee's name and address, on arrival directions and special mail service captions.
The positions of the different entries of course vary depending on the size of the envelope. The operator thus has to remember the relative positions for different envelope sizes. The remembering of the positions and the necessary keyboard manipulations diverts the typist's attention from the entries themselves and thus increases the chances for error.